UTAHN HELPS FINE-TUNE DATING OF QUAKES

A technique a junior high school science teacher helped pioneer during a summer of advanced research on a California earthquake fault could help predict when the next temblor will rock Utah's Wasatch Fault.

Farrell Yeates, Centerville, a science teacher at Roy's Sand Ridge Junior High, worked on a research project last summer using sophisticated carbon dating techniques to determine accurate dates for quakes on California's Hayward Fault.By establishing accurate dates for the quakes, researchers theorize they can determine a time pattern that may help them forecast when the next one will strike.

But until now, establishing accurate dates to within a few years has been impossible. Geologic times are measured in millenia, and a span of 100 or 200 years is a mere tick of the clock.

Working with Livermore Berkeley Laboratory's Dr. Pat Williams, Yeates and fellow researchers dug a 15-foot trench across a branch of the Hayward Fault near the laboratory grounds in Berkeley.

They picked a site rich in carbon deposits, holding the organic remains of plants and animals that succumbed to brush fires and other disasters. Measuring the decay rate of carbon-14, the researchers were able to date the strata where the deposits were found to within a 50-year time span, or window.

The carbon-14 dating process has been used by anthropologists to date pottery fragments and other archeological finds but has never been tried in earthquake research, Yeates said.

By measuring the age of adjacent pieces of faulted strata, they theorized they could put more accurate dates on when the earthquakes occurred. If several quake dates can be established, the hope is that a pattern will emerge, one that will allow more accurate forecasting than in the past.

Yeates participated in the summer of research through a federally funded program designed to give teachers the opportunity to work with full-time scientists in ongoing research projects.

He was one of 29 teachers participating in the lab's Teacher Research Associate program.

It was a hands-on experience, Yeates said. He spent hours in the narrow earthquake trench, smoothing and photographing the walls and picking carbon bits from the earth for analysis.

By giving the researchers access to the laboratory's accelerator mass spectrometer for analysis of the carbon samples, Yeates said a major breakthrough in analyzing the carbon samples was achieved.

Instead of needing a half-pound sample for dating, a speck of carbon as small as four milligrams - about the size of a grain of salt - was found to be sufficient.

That opens the dating technique up to almost any researcher on any earthquake fault, Yeates said, including Utah's Wasatch Fault.

"We found we could do it, we could date an earthquake event within a 50-year window. We were very pleased. That's never been done before," Yeates said.